67results about How to "High remnant polarization" patented technology

The invention provides a method for preparing a Gd and Co codoped high-remanent-polarization BiFeO3 thin film by a sol-gel method. The method comprises the steps that Bi(NO3)3*5H2O, Fe(NO3)3*9H2O, Gd(NO3)3*6H2O and Co(NO3)2*6H2O are dissolved in ethylene glycol monomethyl ether, and then heated and stirred in an 80 DEG C water bath for 1h; acetic anhydride is added and stirred for 1h; a BiFeO3 precursor solution is obtained and stands for 24h; an FTO (Fluorinedoped Tin Oxide)/glass substrate is subjected to spin coating with the BiFeO3 precursor solution for preparing a thin film; the thin film is subjected to rapid annealing at 550 DEG C, and then cooled to a room temperature; and spin coating and rapid annealing processes are repeated till the BiFeO3 thin film with the required thickness is prepared. The adopted sol-gel method does not require expensive equipment, and is suitable for preparing the thin film on a large surface and a surface with an irregular shape; in addition, chemical constituents are precise and controllable; the ferroelectric property of the prepared BiFeO3 thin film is improved under coaction of Gd and Co.

The invention relates to a ferroelectric-antiferroelectric phase transition leadless ferroelectric ceramic material, a ceramic element and a preparation method of the ferroelectric ceramic material. The chemical composition of the ferroelectric-antiferroelectric phase transition leadless ferroelectric ceramic material accords with the chemical general formula of (1-x)Bi0.5Na0.5TiO3-xBiAlO3, wherein 0.01<=x<=0.09. Through composition adjusting and technology improving, the obtained ceramic material has relatively large remanent polarization Pr, the ceramic has ferroelectric-antiferroelectric phase transition (FE-AFE) at a certain temperature, and has important value on practical application of the ceramic to instantaneous pulsed discharge or heat-electrical energy transition and other fields.

The invention belongs to the field of high-polymer blending composite material preparation and discloses a nylon 1111/ polyvinylidene fluoride ferroelectric composite film and a preparation method thereof. The ferroelectric composite film disclosed by the invention is prepared by 20-80 parts of nylon 1111 and 80-20 parts of polyvinylidene fluoride. The preparation method comprises the following steps: firstly blending the nylon 1111 and polyvinylidene fluoride in melt mixing equipment, then hot-pressing the mixture by hot pressing equipment into a film, quenching the molten film and finally stretching by uniaxial tension of a stretching device to obtain the nylon 1111/ polyvinylidene fluoride ferroelectric composite film. The composite film prepared according to the invention exceeds a pure polyvinylidene fluoride film in remanent polarization strength. The preparation method disclosed by the invention has simple preparation process, industrially common equipment and easy operation. The ferroelectric composite film is low in cost, and is expected to be used for apparatus preparations in the fields of piezoelectric, pyroelectric and ferroelectric materials.

The invention provides a Bi0.9Er0.1Fe1-xCoxO3 film with high ferromagnetism and ferroelectricity, and a making method thereof. The method comprises the following steps: preparing a Bi0.9Er0.1Fe1-xCoxO3 precursor solution from bismuth nitrate, iron nitrate, cobalt nitrate and erbium nitrate, spin-coating a substrate with the Bi0.9Er0.1Fe1-xCoxO3 (x is 0.01-0.03) precursor solution, uniformly sizing, drying, and annealing to obtain the Bi0.9Er0.1Fe1-xCoxO3 film with high ferromagnetism and ferroelectricity. The method has the advantages of simple device requirements, easy reaching of experiment conditions, easy control of the doping amount, and great improvement of the ferromagnetism of a BiFeO3 film, and the Bi0.9Er0.1Fe1-xCoxO3 film made in the invention has the advantages of good uniformity, high magnetic intensity and high remanent polarization.

The invention discloses a potassium-sodium lithium niobate-base lead-free piezoelectric ceramic complex with good temperature stability, a preparation method and application thereof. The general formula of the complex is as follows: (1-x) (K0.5Na0.5)0.94Li0.06NbO3-xY, wherein, x is equal to 0-0.05 and Y is a perovskite structural component. The complex has the characteristics of good ferroelectricity, relatively higher remanent polarization, relatively higher piezoelectric property, high Curie temperature, low room-temperature dieiectric loss and good temperature stability, thus being applicable to devices such as a piezoelectric actuator, an energy converter, a sensor, a buzzer and the like.

The invention relates to a method for enhancing photocatalysis performance of a ferroelectric material through regulation and control of spontaneous polarization, an insulation film is prepared by employing soluble high-molecular material-loaded ferroelectric material powder, spontaneous polarization intensity of the ferroelectric material can be adjusted by an applied electric field, photo-induced electron and cavity are effectively separated under effect of intrinsic polarization field, life of a photon-generated carrier is prolonged, so that a purpose of enhancing photocatalysis performance of the material can be achieved. Compared with the prior art, the method provides the simple and effective approach for enhancing the photocatalysis performance of the ferroelectric material (especially the ferroelectric powder material).

The invention discloses a method for preparing bismuth ferrite-barium titanate (BiFeO3-BaTiO3) ceramic through two-step sintering, and belongs to the technical field of lead-free ceramic preparation. The preparation method comprises the following steps: calculating and weighing according to a chemical formula (1-x) Bi (1 + y) FeO3-xBaTiO3, ball-milling and mixing, drying, sieving, putting into an alumina crucible, and pre-sintering at 780-950 DEG C for 2-12 hours to obtain pre-sintered powder; carrying out secondary ball milling, drying at 70-120 DEG C, sieving dried powder, adding polyvinyl alcohol with the concentration of 2wt% into the sieved dried powder, carrying out grinding granulation, and putting the granulated powder into a mold for compression molding; placing the ceramic green body in a muffle furnace, heating to 300-440 DEG C, discharging glue for 2-4 hours, heating to 950-1060 DEG C, preserving heat for 1-10 minutes, cooling to 900-1060 DEG C, sintering for 4-12 hours, and cooling to room temperature along with the furnace to prepare the required ceramic. According to the two-step sintering method disclosed by the invention, by ingeniously controlling the two-step sintering temperature and the heat preservation time, an impure phase generation temperature interval in the bismuth ferrite-barium titanate ceramic can be avoided; the prepared ceramic is good in crystallinity, uniform in component, small in grain size, compact in structure, low in dielectric loss, high in insulativity, high in remanent polarization intensity and excellent in piezoelectric property and photovoltaic property.

The invention relates to a photosensitive ferroelectric polymer composite film and a preparation method thereof, and a ferroelectric device or a piezoelectric device using the composite film. The composite film comprises an organic flexible polymer matrix and inorganic-organic hybrid perovskite filler particles, wherein the content of the filler particles relative to the total mass of the composite film is 1%-5% by mass, and the filler particles exist in the matrix in a monodisperse state.

The invention relates to novel room-temperature multi-ferroic ceramic with high polarization intensity and a preparation method of the novel room-temperature multi-ferroic ceramic. The chemical composition of a room-temperature multi-ferroic ceramic material is 0.75 ((1-x)BiFeO<3>-xBiGaO<3>)-0.25Ba<0.85>Ca<0.15>Ti<0.90>Zr<0.10>O3 +yMnCO<3>, wherein x is greater than 0 and is smaller than or equal to 0.05, and y is smaller than or equal to 0.5wt%. By adjusting and controlling components, the novel room-temperature multi-ferroic ceramic material simultaneously having excellent ferromagnetism and excellent ferroelectricity is obtained, and has high remanent polarization intensity (22-44 [mu]C/cm<2>) and high ferromagnetism properties (0.09-0.27emu/g).

The invention aims to provide a strontium titanate/strontium ruthenate ferroelectric superlattice film material and a preparation method thereof. The material is composed of periodically grown quantumparaelectric insulator strontium titanate and metal conductive oxide strontium ruthenate. The strontium titanate/strontium ruthenate ferroelectric superlattice film material is a high-performance lead-free ferroelectric material, and the residual polarization strength of the high-performance lead-free ferroelectric material reaches 33.0 [mu]C/cm<2>, is 750% higher than that of a traditional lead-free ferroelectric material barium titanate film, and is as excellent as that of a lead zirconate titanate (Pb(ZrxTil-x)O3) lead-based ferroelectric film material that is commonly used at the present.According to the preparation method of the material, strontium ruthenate and strontium titanate are alternately grown on a single crystal substrate through a pulse laser deposition method, and the period thicknesses of a superlattice is accurately adjusted and controlled by controlling the time of laser ablation on different targets. The strontium titanate/strontium ruthenate ferroelectric superlattice film material can be used as the high-performance lead-free ferroelectric material to replace the Pb(ZrxTil-x)O3 lead-based ferroelectric film and has broad application prospects in integratedferroelectric devices such as ferroelectric memories, sensors and actuators.

The invention relates to BNT-BA-KNN leadless ferroelectric phase change ceramic and a preparation method thereof. The chemical constitution of the ferroelectric ceramic material is 0.97((1-x)Bi0.5Na0.5TiO3-xBiAlO3)-0.03K0.5Na0.5NbO3 where x is greater than or equal to 0.01 and less than or equal to 0.04. The ferroelectric ceramic material has ferroelectric-antiferroelectric two-phase coexistence at room temperature, and the remanent polarization strength of the ferroelectric ceramic material is within 33-38mu C/cm<2>. A BNT-BA-KNN tertiary ceramic prepared from the material has characteristics of relatively large remanent polarization strength and ferroelectric-antiferroelectric phase change, and thus the material has significant application values in the technical field of high-power pulse.

The invention provides a Bi[0.85-x]Pr0.15AExFe0.97Mn0.03O3 ferroelectric film and a preparation method thereof. The method comprises the following steps: preparing a Bi[0.85-x]Pr0.15AExFe0.97Mn0.03O3 precursor solution from bismuth nitrate, praseodymium nitrate, hydrogen nitrate AE, ferric nitrate and manganous nitrate, wherein AE is Sr, Ca or Ba, and x=0.02-0.05; spinning the precursor solution on a substrate; and then spinning, drying and annealing, so as to obtain the Bi[0.85-x]Pr0.15AExFe0.97Mn0.03O3 ferroelectric film. The Bi[0.85-x]Pr0.15AExFe0.97Mn0.03O3 ferroelectric film is simple in demands on equipment; the experiment condition is easy to achieve; the doping amount is easy to control; the ferroelectric property of the film can be greatly improved; and the prepared Bi[0.85-x]Pr0.15AExFe0.97Mn0.03O3 ferroelectric film is good in uniformity, low in leakage current, and low in coercive field, and has relatively high remanent polarization.

A method for the annealing preparation of a tantalum scandium acid plumbum-based ferroelectric film by a two step method is disclosed, comprising the technological steps of preparing a transition layer, preparing the tantalum scandium acid plumbum-based ferroelectric film and annealing the tantalum scandium acid plumbum-based ferroelectric film; annealing the tantalum scandium acid plumbum-based ferroelectric film comprises the steps of: putting the tantalum scandium acid plumbum-based ferroelectric film in an annealing furnace, heating up to 800-850 DEG C at a heating rate of 40 DEG C/s in an oxygen flow and then stopping heating up at once so that the tantalum scandium acid plumbum-based ferroelectric film is naturally cooled to 500-600 DEG C along with the furnace, preserving the heat for 3-5 minutes, and afterwards naturally cooling the ferroelectric film to room temperature along with the furnace. The tantalum scandium acid plumbum-based ferroelectric film prepared by the method has a perovskite phase purity capable of reaching 100%, good crystallization performance and low RMS roughness on the surface as well as also has the characteristic of high polarization intensity and high preferred orientation.

The present invention relates to a manganese-doped BNT-BA lead-free ferroelectric ceramic material and a preparation method thereof, wherein the chemical composition of the manganese-doped BNT-BA lead-free ferroelectric ceramic material is 0.96Bi0.5Na0.5(Ti1-xMnx)O3-0.04BiAlO3, and x is more than or equal to 0.1% and is less than or equal to 1.0%. According to the present invention, the prepared manganese-doped BNT-BA binary ceramic has excellent comprehensive electrical properties and is expected to be applied in the technical field of high-power pulses.

The invention relates to a ceramic composite with a bismuth layer structure with good comprehensive performance in high-temperature piezoelectricity, dielectric and so on. The chemical formula of the ceramic composite is (Sr2-xCax)1-yMyBi4Ti5O18, wherein M can be one or more of Mn, Ba, Ce, Pb and other elements; x is more than or equal to 0 and is less than or equal to 2, and y is more than or equal to 0 and is less than or equal to 1. The composite has good performance when x is equal to 1 and y is equal to 0, and the Curie temperature is more than or equal to 570 DEG C. At room temperature, piezoelectric constant d33 is more than or equal to 22pC.N<-1>; d33 is more than 17pC.N<-1> at a temperature of 550 DEG C, and 80 percent of the piezoelectric activity is still maintained. From room temperature to 550 DEG C, the dielectric loss of the composite in 100 kHz is less than or equal to 0.07, and the dielectric loss of the composite in 1MHz is less than or equal to 0.02, and the specific inductive capacity-temperature coefficient is small. The ceramic composite can fulfill the application in steel, chemical engineering, energy, aerospace engineering and other industrial fields.

The invention discloses a BT-KBT-NN (BaTiO3-K0.5Bi0.5TiO3-NaNbO3)-based high energy storage density ceramic and a preparation method thereof. The preparation method comprises the following steps: firstly, preparing BT presintering powder, KBT presintering powder and NN presintering powder; then, carrying out burdening on the BT presintering powder, the KBT presintering powder and the NN presintering powder according to a chemical formula (1-x)(0.92BaTiO[3]-0.08(K[0.5]Bi[0.5])TiO[3])-xNaNbO[3], wherein x is 0.02-0.08, and x is a mole percent; evenly mixing, drying, tabletting, and forming to obtain mixed tablets; then, sintering the mixed tablets to obtain the BT-KBT-NN-based high energy storage density ceramic.

The invention discloses a bismuth ferrite film material, a method for integrally preparing a bismuth ferrite film on a silicon substrate at a low temperature and application. The method comprises: under the condition of 300-400 DEG C, a bottom electrode, a buffer layer and a bismuth ferrite film being sequentially subjected to magnetron sputtering on the surface of a base body from bottom to top,reducing the temperature to the room temperature, a top electrode being subjected to magnetron sputtering on the surface of the bismuth ferrite film, and the buffer layer being made of conductive oxide which can be matched with bismuth ferrite lattices and is of a perovskite structure. The temperature for preparing the bismuth ferrite film material can be reduced to 450 DEG C or below, and the bismuth ferrite film material has high polarization strength.

SrBi₂Nb₂O₉ (SBN) thin films are deposited on Pt/TiO2/SiO2/Si substrates using off-axis pulsed laser deposition technique. Off-axis laser ablation avoids plasma damaging of the surface of SBN thin films and is favorable to grow films along the polarization axis (a–b plane). SBN thin films are grown at 350° C. substrate temperature, with 5 mm away from the plasma focus, and annealed at 750° C. for 1 hour in oxygen ambient. These SBN thin films exhibited giant remnant polarization (P_r) of 50 μC/cm² with coercive field of 190 kV/cm. The fatigue endurance of these SBN thin films was measured at 400 kV/cm and showed minimal (<20%) polarization degradation of up to 10¹⁰ switching cycles. The leakage current density of SBN thin films was found to be about 2×10⁷ up to an applied field of 100 kV/cm. The above-mentioned properties of off-axis deposited SBN thin films, makes it a good material for NVRAM devices.

The invention relates to Sb2O3-doped ZnOw/PZT biphase piezoelectric composite ceramics and a preparation method thereof, and belongs to the field of inorganic non-metallic material science. The Sb2O3-doped ZnOw/PZT biphase piezoelectric composite ceramics comprise the following raw materials: Sb2O3 powder, nano ZnO crystal whiskers and plumbum zirconate titanate (PZT) ceramic powder. The preparation method comprises: uniformly mixing the ZnO crystal whiskers, the PZT powder and the Sb2O3 powder first, adding a polyvinyl alcohol solution in a system for ball milling and stirring, performing drying, crushing, fine grinding, sieving, and dry pressing and forming, preparing the composite ceramics through binder removal and sintering, and performing cutting processing and polarization aging. Compared with the prior ZnOw/PZT piezoelectric ceramics, the Sb2O3-doped ZnOw/PZT biphase piezoelectric composite ceramics greatly improve the prior piezoelectricity and strengthen the mechanical property, are novel biphase piezoelectric composite ceramics with wide application prospect, have simple preparation operation technique and low cost, and can meet the requirements of industrial promotion and application.

;An enhanced high-electron-mobility transistor based on ferroelectric III nitride polarization reversion comprises a substrate, a nucleating layer, a buffer layer, an insertion layer, a barrier layer and a passivation layer in sequence from bottom to top and the barrier layer comprises a non-ferroelectric barrier layer and a ferroelectric group III nitride barrier layer, and the ferroelectric group III nitride barrier layer is arranged between the non-ferroelectric barrier layer and the passivation layer. The buffer layer and the barrier layer form heterojunctions with different forbidden band widths, and the forbidden band width of the buffer layer is smaller than the forbidden band width of the barrier layer; two ends of the upper surface of the buffer layer are provided with a source electrode and a drain electrode; and a gate electrode is arranged on the ferroelectric III nitride barrier layer, and the gate electrode is nested in the passivation layer. The buffer layer and the barrier layer are made of III-V group semiconductor materials, the preparation processes of the buffer layer and the barrier layer are compatible, the film growth quality of each layer is high, and the interface characteristic between the films is good; and meanwhile, the ferroelectric hysteresis loop rectangularity of the group III nitride ferroelectric material is high, the remanent polarization intensity is high, the retention time of the closed and on states of the device is long, and the service reliability is higher.

The invention relates to a ferroelectric ceramic material with high dielectric withstanding voltage, high remanent polarization, low loss and low sintering temperature, a preparation method of the ferroelectric ceramic material and a piezoelectric element prepared from the ferroelectric ceramic material. The ferroelectric ceramic material contains components as follows: Pb(1-x)Cdx(Zr0.965Ti0.035)O3(x=0-0.03)+1wt%Nb2O5+bwt%Li2CO3(PCZT95/5). The compact PCZT95/5 ferroelectric ceramic material with high dielectric withstanding voltage, high remanent polarization and low loss is prepared through addition of CdO and Li2CO3 and adjustment of proper Zr/Ti ratio under the condition of reducing the sintering temperature from 1350 DEG C to 1050 DEG C, the ferroelectric ceramic material is applicable to a multilayered PCZT95/5 thick-film device, the problem that mechanical strength and electric breakdown resistance of a monolithic PZT95/5 are not high after bonding currently is solved, and meanwhile, the ferroelectric ceramic material is greatly helpful for reliability and miniaturization of the device and has great application prospect in the aspects of industrial and national defense fields of explosive ferroelectric power supplies.